A young man walks into a bike shop staffed by one 70 yo duffer. Takes a look at a high end bike. While the shopkeeper has his back turned, young man races out the door with his conquest, a several thousand dollar road bike, jumps on and is gone. But the duffer grabs his bike, probably a time honored steel bike, and goes in pursuit. After a while, young man looks over his shoulder. That old man isn't far behind! He steps it up. But that old man isn't quitting! Several miles later, an exhausted bike thief hits a pedestrian and crashes. Old man pulls up, dismounts and stands guard until the police show up.

The old man? John Allis. Could have sustained that chase another, what, 20 miles?